Bug#44684: valgrind reports invalid reads in

Item_func_spatial_collection::val_str
        
When the concatenation function for geometry data collections
reads the binary data it was not rigorous in checking that there
is data available, leading to invalid reads and crashes.
Fixed by making checking stricter.


mysql-test/r/gis.result:
  Bug#44684: Test result
mysql-test/t/gis.test:
  Bug#44684: Test case
sql/item_geofunc.cc:
  Bug#44684: fix(es)
  - Check that there are 4 bytes available for type code.
  - Check that there is at least one point available for linestring.
  - Check that there are at least 2 points in a polygon and
    data for all the points.

1 files changed, 10 insertions, 3 deletions

diff --git a/sql/item_geofunc.cc b/sql/item_geofunc.cc
index 24a92c78e9c..a34204b7181 100644
--- a/sql/item_geofunc.cc
+++ b/sql/item_geofunc.cc
@@ -416,7 +416,10 @@ String *Item_func_spatial_collection::val_str(String *str)
     else
     {
       enum Geometry::wkbType wkb_type;
-      const char *data= res->ptr() + 4/*SRID*/ + 1;
+      const uint data_offset= 4/*SRID*/ + 1;
+      if (res->length() < data_offset + sizeof(uint32))
+        goto err;
+      const char *data= res->ptr() + data_offset;
 
       /*
 	In the case of named collection we must check that items
@@ -439,7 +442,7 @@ String *Item_func_spatial_collection::val_str(String *str)
 	break;
 
       case Geometry::wkb_linestring:
-	if (str->append(data, POINT_DATA_SIZE, 512))
+	if (len < POINT_DATA_SIZE || str->append(data, POINT_DATA_SIZE, 512))
 	  goto err;
 	break;
       case Geometry::wkb_polygon:
@@ -448,11 +451,15 @@ String *Item_func_spatial_collection::val_str(String *str)
 	double x1, y1, x2, y2;
 	const char *org_data= data;
 
-	if (len < 4 + 2 * POINT_DATA_SIZE)
+	if (len < 4)
 	  goto err;
 
 	n_points= uint4korr(data);
 	data+= 4;
+
+        if (n_points < 2 || len < 4 + n_points * POINT_DATA_SIZE)
+          goto err;
+        
 	float8get(x1, data);
 	data+= SIZEOF_STORED_DOUBLE;
 	float8get(y1, data);